Plankton are small, often microscopic, creatures that largely just drift with the ocean current (as opposed to animals like fish that can swim through the current). Despite being small, they pack a big punch in marine ecosystems because a wide variety of marine life survives only by eating plankton.

Small plankton volume

A figure showing the trends in the average volume of small plankton (tiny, often microscopic creatures floating in the water) collected in the ocean off of Southern California from 1978 to 2015. Data source: CalCOFI; Figure credit: A. Thompson/NOAA.

A figure showing the trends in the average volume of small plankton (tiny, often microscopic creatures floating in the water) collected in the ocean off of Southern California from 1978 to 2015. Data source: CalCOFI; Figure credit: A. Thompson/NOAA.

Click for Details Mean volume of small plankton collected in net samples during CalCOFI cruises at only sites in the Channel Islands National Marine Sanctuary region (top) and all sites over the Southern California Shelf (bottom) from 1978 to 2015 (sampling locations shown in Figure App.F.12.17). Horizontal lines show the mean (dashed line) ± 1.0 standard deviation (solid lines) over the full time series. Symbol at upper right indicates whether data over the last five years (green shaded areas) had a positive trend ( ), a negative trend (), or no trend (↔). Symbol at lower right indicates whether the mean over the past five years was greater than (+), less than (-), or within 1 standard deviation (●) of the mean of the full time series. For more information, consult Figure App.F.12.18 in the CINMS 2016 Condition Report.